Frazier Campbell was so excited by the prospect of making his Cardiff City debut against Leeds that he was up at 7am on Saturday morning. The early riser may have had a curtailed sleep but what followed when he stepped onto the Elland Road turf as a 61st-minute substitute really was the stuff of dreams, Campbell scoring the only goal within two minutes. "It's been a long time since I've been able to think I'm going to be involved in a game," he explained afterwards. "I was really excited and I couldn't have wished for a better start."

A Yorkshire lad, Campbell joked that he had "upset a couple of my family members" with his winning strike – deflecting a Craig Bellamy shot past Paddy Kenny – yet it provided immediate vindication for Cardiff manager Malky Mackay's decision to invest £600,000 in a 25-year-old whose career has yet to fully ignite, despite moments of genuine promise.

"I know to my cost what he is like in this division," said Mackay, who was on Watford's coaching staff when they lost to Campbell's Hull in the 2007/08 Championship play-off semi-finals. Campbell hit 15 goals that year but has played little football in recent seasons. In August 2010 he suffered a cruciate ligament injury which required two operations and an 18-month absence. Though he won his first England cap within a month of his return – as a late substitute against Holland on the same night last February that his daughter was born – he scored only one league goal subsequently for Sunderland before joining Cardiff.

Yet Mackay is confident he can make an impact. "He is a really willing runner, an intelligent footballer and someone who knows where the goal is," he said. "We've given him that chance again to prove himself and he absolutely wants to be part of it and has bought into the team ethic."

That team ethic was in clear evidence again at Leeds, where the Championship leaders, fresh from a training break in Dubai, won to go 10 points clear. "The lads were brilliant from the front to the back" was Campbell's verdict, though this performance tallied with the opinion expressed by Kevin Ratcliffe, the former Wales captain, in the press room beforehand that Cardiff are solid rather than spectacular.

This was their 11th win in 14 Championship outings, but 10 have come by a single goal and this was an object lesson in keeping it tight and nicking it. As Mackay said: "We applied ourselves really well and when times of quality were needed, then we showed that."

Cardiff have a strong, experienced spine in Mark Hudson, Peter Whittingham and Craig Bellamy, and like all good teams know how to profit from the luck that Neil Warnock, the Leeds United manager, felt came their way during Saturday's tight contest, taking advantage of the home defence's one big lapse to snatch the winner and then enjoying the rub of the green as referee Mike Dean failed to spot a Hudson handball in his own box.

A return to the top flight after 51 years now appears imminent. Cardiff have fallen in the play-offs in each of the past three campaigns but thanks to their Malaysian owners' £10m investment in 10 new signings last summer, they have the strength in depth to sustain their challenge.

"We're going to need that in the next 17 games," Mackay said. "It's what we were lacking last year – I had to flog dead horses last year and this year we've managed to have a bench that has strength on it."